How much CO2 does a tree absorb?

Published on Feb 9, 2022

We have seen the news about the Smog Tower inaugurated in Delhi in Aug 2021. But they are found to be half the effectiveness than it was claimed, as reported by The Hindu

Nature has a cure on its own which we have been ignoring, in fact cutting those down. In this blog, we will be seeing if a tree is effective in removing CO₂ and understanding how much it can.

We were unsure about this task because there are hundreds of varieties of trees. But do you know what stands out?
They all follow a process called Photosynthesis, one of the earliest processes we have learnt in our childhood. This process is used by the trees to absorb CO₂, in combination with water, to produce sugars(glucose dominant) using Sunlight. The walls of most trees, with chains of hundreds of glucose molecules, combine to form a similar chemical component called Cellulose (C₆H₁₀O₅).

Source: Pixabay

Having understood how trees use photosynthesis to build carbon molecules & in fact the majority of the tree itself by absorbing CO₂, let’s look at how much CO₂ can the tree absorb:

Let’s take a tree 20 feet tall(H) and 15 inches(D) in diameter.

Weight of the tree above ground Wₐ= 0.25*D²*H = 0.25*(15)²*20
= 1125 pounds= 510 kg (approx.)
Roots constitute 20% of the total weight of the tree on an avg. So, the total weight of the tree W= 120% * Wₐ = 120%*510 = 612 kg

Of this total weight, the tree(taking varieties of species into consideration) has a moisture content of about 27.5% to prevent forest fires and circulate nutrients. The rest 72.5% is the dry mass.
Weight of dry mass W𝒹 = 72.5 * W = 443.7 kg

And Carbon formed by photosynthesis discussed above forms about 50% of this dry mass.
W𝒸 = 50%* W𝒹 = 50% * 443.7 = 221.85 kg

Each carbon atom is from one CO₂ molecule. So, how much CO₂ is absorbed to form 1kg carbon?
Carbon atomic mass is 12 while CO₂ is 44, which means 1kg of Carbon is formed using (44/12)= 3.67 kg CO₂.

For 221.85kg of CO₂ to get absorbed W𝒸, this tree would have absorbed = 221.85 * 3.67 = 814kg CO₂ (approx.)

Assuming the tree is 30 years old, it would have absorbed = 814/30 ~ 27kg CO₂ annually.
Under various climate conditions, a tree generally absorbs 10–40kg of CO₂ annually. Now imagine a park of 30 trees. It can easily absorb CO₂ emissions annually from a car.


It’s a pleasure to share such information with you because we believe sharing and understanding such information will make this world a better place. The above wouldn’t have been possible without content from the University of New Mexico and Ecotree.

Written by Zodhya

About Zodhya

We are Zodhya, a start-up that provides AI-based tech to reduce energy bills and lower emissions for commercial buildings and industries.